This application claims the priority of German application 100 29 467.7, filed Jun. 21, 2000, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to a method for the production of reinforced hollow sections with a continuous periphery.
In order to reinforce a hollow section, the customary practice is to weld reinforcing plates to a hollow section. This type of reinforcement is often obstructive when fitting these kind of hollow sections in restricted spaces because of their large size. To compensate for the large size, the entire component would have to have a smaller cross section, thus reducing the strength of the component. This is very importance in the construction of motor vehicles, especially when producing axle beams.
The object of the present invention is to provide a production method which makes it possible in a simple manner to provide hollow sections with selective local reinforcement at points subject to high mechanical loads.
According to the present invention, an opening is introduced into the hollow section from outside at the point to be reinforced. This impairs neither the functionality of the hollow section nor its basic rigidity. A reinforcing plate is then introduced into the opening and joined to the hollow section in the region of the opening, giving rise locally to a multi-chamber section in the hollow section. This multi-chamber section represents a reinforcement of the hollow section, maintaining the characteristics and shape of the hollow section even when hollow sections with reinforcing plates welded on in the conventional manner collapse due to high mechanical loads. By means of the multi-chamber section, higher rigidities are achieved due to higher geometrical moments of inertia. This can be simply achieved even at points on the hollow section that are relatively inaccessible due to its shape. Moreover, there is no waste of installation space urgently required for other purposes. The reinforcing plate can have any desired shape. Another advantage of such method is the relatively low consumption of materials and thus the weight of the overall component is only slightly increased. The characteristics of welded-on plates, in contrast, depend on the surface of the component to be reinforced. This can be a very large surface and highly unconducive to effective welding attachment. In the case of joining by welding in accordance with the invention, the lengths of the weld seams for joining the reinforcing plate are significantly shorter than with external welds, with the result that less heat is introduced into the hollow section, thus reducing distortion of the material and therefore reducing the amount of finishing work.